The invention relates to ice removal and, more particularly, to an ice chipping and removal system including a pair of vertical, rotatable drums.
In the petroleum exploration and production industry it is often necessary to move men and equipment through relatively hostile environmental regions. In recent years the emphasis on oil production from the far north has necessitated development of new techniques for moving materials through the Arctic regions.
In the Arctic, large regions are often covered by thick layers of ice and snow. As these layers move about, their edges override one another and form pressure ridges and hummocks in the ice. Hummocks are ice regions which are harder than the surrounding ice, have a very smooth outer surface and are formed when a pressure ridge heals itself through years of weathering. The arctic terrain is also shrouded by snow drifts which collect against the pressure ridges. In order to conduct petroleum production activities in the Arctic it is desirable to level off the pressure ridges and other protuberances which contribute to an extremely rough ice surface, for example, a smooth road surface must be formed through the rough ice in order to move vehicles and equipment across it.
One prior art system which has been used to smooth a path through the rough ice includes a large, toothed drum rotatable about a horizontal axis. The drum is supported on skids pushed by a large tractor and is rotated independantly from the bottom upwardly to undercut the ice. The major problem with such horizontal drum cutters is that when snow is encountered it is difficult to know what is beneath the snow, such as where the top surface of the ice is located. Since a rotating horizontal drum cuts ice equally well in both the vertical and horizontal directions, if the skids fall into a snow filled hole before the rotation of the drum can be stopped it may cut all the way down through the ice and take the tractor and operator with it through the hole into the underlying water. Needless to say, such systems have proven dangerous to both men and equipment.
Prior art snow removal systems, such as that disclosed in U.S. Pat. No. 1,615,461 to E. H. Lichtenberg, have sought to provide a pair of vertical rotating cutters for flaking the snow and moving it toward the intake of a blower which throws the snow away from the roadbed being cleared. While the Lichtenberg machine includes vertical rotating cutters, it would not be adaptable for cutting ice because of the lack of cutting teeth and augers for removing the ice chips. Further, the Lichtenberg cutters rotate toward one another to move snow into the blower while the present drums include overlapping teeth and rotate in the opposite direction, away from one another, to produce a forwardly directed force tending to move the machine through the ice.
Similarly, ice cutting equipment such as that shown in FIG. 1 of U.S. Pat. No. 3,696,624, entitled Bucket Wheel Ice Cutter, to John D. Bennett, the present inventor, employs counter-rotating bucket wheels mounted on the front of a ship. Such marine systems are designed primarily to cut through the entire thickness of a floating ice sheet and the cutting wheels do not include such features of the present drum cutters such as augers to remove ice chips from the path and a bottom drum surface which prevents cutting in the vertical direction except when desired. Further, in the prior art cutter the paths of the counter-rotating bucket wheels do not overlap in the region between the wheels to produce a forwardly directed force as in the system of the present invention.
It is therefore an object of the present invention to provide an improved system for cutting and removing ice and, more particularly, for forming an elongate, relatively smooth path through a rough snow and ice covered terrain. The system of the present invention provides a more efficient and relatively safe means for clearing a road through ice and snow.